Snow plow



Oct. 20, 1942. E. w. AUSTIN SNOW PLOW Filed Jan. 27, 1941 4 Sheets-Sheet 1 BY E mama/$ M 322% Oct. 20, 1942. E. w. AUSTIN 2,299,451

SNOW PLOW Filed Jan. 27, 1941 4 Sheets-Sheet 2 ZZbaJQrZ/WZH K2 2 5722 INVENTOR.

1 31.- Ill Oct. 20, 1942.. E. w. AUSTIN SNOW PLOW Filed Jan. 27, 1941 4 Sheets-Sheet 3 d Qm I77 l- L a A 6% INVENT OR. 0 E'ZZflz/m'Z/W M BY 9 cal 50; 1942.

E. W. AUSTIN SNOW PLOW 4 Sheets-Sheet 4 Filed Jan. 27, 1941 Patented Oct. 20, 1942 SNOW PLOW Ellsworth W. Austin, Cedar Rapids, Iowa, as-

signor to La Plant-Choate Manufacturin g Co.,

. Inc., Cedar Rapids, Iowa, in. corporation of Delaware Application January 27 1941, Serial No. 376,041

29 Claims.

My present invention relates to a snow plow which includes a blade of V formation and wings which form extensions of the outer ends of the blades.

One object of the invention is to provide a snow plow which may be readily and simply constructed .of few parts, yet which includes mechanism for efliciently supporting the wings so that they may be swung upwardly or downwardly as desired and also hinged rearwardly from their extended position as desired.

Another object is to provide a snow plow consisting of blades which have rigid arms extending rearwardly therefrom for pivoting at the sides of 'a tractor, the blades being hinged together so that they may be swung to a closed position to decrease their overall width when shipping the snow plow.

Still another object is to provide wings which are swingably carried by the snow plow blades so that they may be swung upwardly as desired, the swinging connection taking the form of a double link arrangement for controlling the inclination of the wing in its various positions.

A further object is to provide the wings hingedly connected to the links so that they may be swung close to the sides of the tractor when their use is undesirable, or swung outwardly for widening the path cut by the snow plow, hydraulic jacks being provided as a convenient means for controlling the swinging and hinging of the wings from the operator's cab.

Still a further object is to provide a set of valves for operating the hydraulic jacks and a bracket for supporting the packs which control the hinging of the wings, such bracket being in the form of a cover for the valve mechanism and being swingably mounted on the tractor so that it may be swung out of the way when it isdesirable to gain access to the valves for repair or renewal 40 Figure 3 is a rear perspective view of one of the blades of the snow plow and its wing:

Figure 4 is a plan view of the plow with a portion at the right side of the figure broken away;

Figure 5 is a diagrammatic plan view showing how the blades of the plow may be swung together due to a hinge connection between them when it is desirable to ship the snow plow;

Figure 6 is a plan view of a bracket and hydraulic jack valve mechanism of my snow plow;

Figure '7 is a rear elevation of Figure 6; Figure 8 is a side elevation thereof showing by dotted lines the position of the bracket'for gaining access to the valves;

Figure 9 is a sectional view on the line 99 of Figure 1;

Figure 10 is a similar sectional view showing a modification;

Figure 11 is a rear elevation of one of the snow plow blades and one of the wings showing modification, and s Figure 12 is a similar view showing another modification.

On the accompanying drawings, I have used the reference character T to indicate generally a tractor. The tractor T is of the track laying type having tracksv l0, although of course my snow plow may be mounted on other types of tractors as well. On the track frames of the tractor T, I mount brackets l3 and I4 which are preferably formed of steel plates welded together. The brackets l3 carry pivot pins [5 on which arms l6 are pivoted. Removable keys I! serve to retain the arms on the pins.

Each arm [6 is welded or otherwise rigidly secured to the rear face of a snow plow blade ll. Two of the arms 16 and two of the blades H are provided, the blades being connected together by hinge connections indicated at l8.

At the parting line between the two blades l1; the right-hand blade is provided with a relatively wide flange l9 and the left hand blade with a relatively narrow flange 20. The flanges I9 and 20 are bolted together by bolts 2| (see Figure 9). The flange l9 serves as a dividing board during operation of the snow plow.

The bolts 2| may be removed and the plow blades I1 and their arms l6 folded to the solid line position shown diagrammatically in Figure 5 when it is desirable to ship the snow plow. Its overall width is thus considerably reduced, as is evident by comparing the dotted showing in Figure 5 with the full line showing therein. Thus, a snow plow which is too wide to shipe by truck or on a freight car, where maximum widths are vthe outer ends of the blades I1.

specified, may be effectively reduced in width due to the hinge connections I8. The hinge pins may also be removable if it is desirable to further decrease the width by separating the two halves of the snow plow.

In Figure 10, a modification is shown wherein each of the snow plow blades I1 is provided with a narrowflange 28 and a relatively wide flange l9a is bolted between'them by the bolts 2 I. With this form of construction, the flange I9a= serves as a dividing board when desired, but .when the dividing board is not desired it can be removed and the flanges 28 bolted directly together.

I provide wings 22 which form extensions of Each wing22 is hinged to a plate 23, the hinge Din being indithe wing and thereafter, whenever the wing is elevated, it will assume such inclination.

If it is desirable to have a considerable inclination to the wing 22 when in its elevated position, the construction may be somewhat simplified, as in Figure'12. In this figure, instead of having a pair of links 29, an arm 69 is provided having a single pivot at 38b.- The arm 68 is thereby a for each blade. For elevating the blades when it cated at 24. The hinge pin is substantially .ver-

tical whereby the outer end of the wing may be swung rearwardly as desired. The plate 23 is 'slidable in a slot 25 formedbn one side bythe back of the bladeand on its other side by a vertical reenforced member 26 secured to the blade arm I6. Further reenforcement is provided by a diagonal brace 21 from the member 26 to the arm I6. Each plate 23- is preferably provided with a pair of rollers 23a for travel in the slot 25.

The plate 23 carries hinge pins 28 to which the outer ends of links 29 are pivoted forming a portion of a power-operated elevator for the.

wing in each case. The inner ends of the links 29 are pivoted at 38 to the back of the blade I! adjacent the apex of the V. A brace link 3| is pivoted at 32 to the links 28 for further reenforcement. It is believed obvious that due to the link connection 29 the plate 23 may be slid upwardly in the slot 25 for thereby elevating the wing 22 (see dotted position in Figure 3). The link connection is so arranged that the inclination of the wing will change from substantially level position when adjacent the ground surface, to a slight upward'and outward inclined position when elevated. The inclination of'the elevated position, however, will not be as great .as if the parts 23 and 29 were rigid and merely pivoted at one point instead of on the two pivot points 38. I may thus secure any desired inclination of the wing when elevated by properly dimensioning the links 29 and the spacing of ,the pivots 28 and 38 with relation to each other.

The angle of the wing 22 with relation to the plow blade I! may also be changed to some extent by pivoting the wing 22 at El to a bracket 62 which carries the hinge pin 24. Slot and bolt connections 6364 are provided for. fixing the wing with relation to the bracket. The angle of the wing may be changed within the limits of the slots 63' while the bolts 64 are loose and the bolts then tightened to retain the adjustment.

With the wing at the desiredinclination when adjacent the ground surface, it may be changed as to the inclination it will assume when it is in its elevated position by an adjustable connection such as shown in Figure 11. In this figure the lower link 29, instead of having a stationary pivot, is provided with a pivot 38a carried by a slide plate 65. The plate is guided in a pair of Z bars 66 welded to the back of the blade I! and its elevation is determined by a screw 61. The screw 61 may be rotated in the appropriate direction for raising or lowering the pivot 38a as desired. When it is raised, the inclination of the wing 22 in its elevated position will be greater, while such inclination will be less when the bracket 65 is lowered. The bracket of course is adjusted to secure the desired inclination of Y is desirable to operate the plow above the ground For controlling the elevation of the wings 22, I provide hydraulic jacks 48 pivoted at one end to brackets 4| adjacent the apex of the V and pivoted at their opposite ends to triangular plates 35. The plates 35 are pivoted at 36 to the brackets l3 and are connected by links 31 to brackets 38 mounted on the arms l5. Rollers 39 are carried by the brackets 38 to guide the arms by engaging the brackets I4.

For controlling the elevation of the wings 22, I provide hydraulic jacks 48 pivoted at one end to brackets 4| adjacent the apex of the V and pivoted at their opposite ends to brackets 42 secured to the lower links 29.

For controlling the hinging of the wings 22, I provide hydraulic jacks 43 pivoted at one end by a universal joint connection to brackets 44 on the backs of the wings 22, and at their other ends by universal joint connections to a relatively large bracket 45. If desirable, the jacks 43 may include piston rods 45 which are telescopically arranged in tubes 41 sothat a plurality of openings in the rod and a removable pin 48 therefor may be utilized for lengthening or shortening the jack connections 43.

A multiple valve 49 is provided for controlling the flow of oil under pressure to the various jacks 34, 48 and 43. Since the valves themselves and the hydraulic connections are conventional, they are not illustrated in detail. The valve 49 is mounted on the back of the tractor T and is covered by the bracket45. The bracket 45 also carries an oil supply tank 58 for the hydraulic jack system, from which a flexible hose 5| depends to a position for coaction with an intake nipple 52 of the valve 49. v

For operating the various units of the valve 49 from inside the cab 53 of the tractor T, control rods 54 extend from inside the cab into a housing 55. Within the housing 55, bell cranks 55 operatively connect the rods 54 with the units'of the valve 49 by means of links 51.

The bracket 45 has been designed to form a protective covering for the valve 49 and its various connections. To gain access to the valve, the bracket 45 is pivoted to a pair of sub brackets 58 mounted on the tractor T and bolted at 59 to another pair of sub brackets 68 mounted on the tractor. The bolts 59 may be removed, the hose 5I disconnected from the nipple 52 and the jacks 43 disconnected from the bracket 45, whereupon the bracket 45 may be swung to the dotted position of Figure 8 to gain ready access to the valve 49 and th bell crank housing 55.

From the foregoing description," it is' obvious that I have provided a snow plow structure wherein the plow may be readily reduced in width for shipping purposes. During operation of the plow, the wings 22 may be lifted to a relatively-,high position so as to roll the snow up and completely out of theway. The wings may be lowered when a wide swath is-tobeplowed and readily raised to clear obstructionsby aconvenlent control within the cab ofthe tractor. Also, the plow may proceed in a straight line down the highway with the wings swung outwardly, but when an obstruction such as a tree or mail-box is encountered the wing may be quickly swung in to clear the obstruction and then swung out again after the obstruction is passed. The hinged arrangement of the wings also makes for convenience in passing across narrow bridges and the like.

Mounting the wings on the backs of the blades in the manner illustrated minimizes the number of parts, yet provides a rigid mount for the wings, as distinguished from types of mountings now in general use, including supporting cables and the necessary framework fOr them. The result is a decided improvement in visibility, as there are no frame parts projecting into the line of sight of the driver. Elimination of the cables also provides for greater accessibility to any part of the plow. By having the wings mounted back of the blades, they form efiective extensions of the blades, as the snow rolling off the outer edges of the blades is picked up by the wings, thus forming a clear plowed path.

' The bracket 45 serves as an effective protector for the valve mechanism, yet may be readily swung to a position out of the way when it is desirable to repair or renew parts of the valve.

As many changes could be made in the foregoingconstruction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be considered as falling therebetween.

I claim as my invention:

1. In a snow 'plow, a pair of blades hinged together in V formation, arms rigidly connected at their front ends to, and extending rearwardly from, said blades along the sides of a track type tractor, the rear ends of said arms being pivotally secured to the track frames thereof, hydraulic jack connections between said tractor and said arms to raise said arms, shoes for supporting said blades with respect to the ground surface, said blades having cooperating flanges at their meeting ends, and means for securing said flanges together to fix one blade rigidly relative to the' other one.

2. In a snow plow, a pair of blades hinged to gether in V formation, an arm extending rearwardly from each of said blades and pivotally secured at its rear end to a tractor, said arms each being rigid with relation to its respective blade, means to adjust the elevationof said of said blades together to fix one blade rigidly relative to the other one.

3. In a snow plow, a pair of blades detachably hinged together in V formation, an arm rigidly secured to each of said blades and extending rearwardly therefrom for connection to a tractor, said blades having cooperating flanges at their meeting ends, and means for bolting said flanges together to fix one blade rigidly relative to' the other one, at least one of said flanges being wide enough to serve as a dividing board.

4. In a snow plow, a pair of blades hinged together for collapsing to a position of less width than normal, an arm rigidly attached to and extending rearwardly from each of said blades and adapted to be operatively. secured at their rear ends to a tractor, said blades having cooperating detachable means at their meeting ends which may be attached together to flx one blade rigidly relative to the other one.

5. In a snow plow, a pair of plow blades hinged together in V formation, a traction arm extending rearwardly from each of said blades, said blades having cooperating flanges at their meeting ends, means for securing said flanges together to fix one blade rigidly relative to the other one, wings forming extensions on the outer ends of said blades, said wings being swingably carried by said blades with the hinge adjacent the apex of the V' to permit the wings to be swung upwardly and simultaneously therewith swung from a substantially level position when adjacent the ground surface to an upwardly and outwardly inclined position when elevated, and hydraulic jacks carried by each blade on the back thereof to effect elevation of said wings.

6. In a snow plow, a plow blade, a wing forming an extension on the outer end of said blade, upper and lower links adjacent the back of said blade, said links each having one of their ends pivoted to said blade and their other ends pivoted to said wing adjacent the inner end thereof whereby to permit the wing to be swung upwardly and simultaneously therewith swung from a substantially level position when adjacent the ground surface to an upwardly and outwardly inclined position when elevated, and means carried by said blade on the back thereof to effect swinging of said links and thereby elevation of said wing.

7. A snow plow comprising a pair of blades hinged together in V formatiomarms extending rearwardly from .said blades and adapted for attachment to a tractor, wings forming extensions on the outer ends of said blades, upper and lower links adjacent the back of each blade for mounting said wings thereon, said links 'each having one of their ends pivoted to said blade and their other ends pivoted to said wing whereby to permit the wings to be swung to an upwardly and outwardly inclined position, and means to effect swinging of said links and thereby elevation of said wings.

blades. and means for securing the adjacent ends 8. In a snow plow, a plow blade, means for mounting said plow blade on atractor or the like in front of the same, wings forming extensions of the ends of said blade, a set of upper and lower links adjacent the back of the blade for supporting each wing and swingably mounting it on the blade, said links each having one of their ends pivoted to said blade adjacent the center thereof and their other ends pivoted to said wings adjacent the inner ends thereof whereby to permit the wings to be swung upwardly from a substantially level position when and inwardly when the .wing is up.

adjacent the'ground surface to an upwardly and outwardly inclined position when elevated, means carried by said blade on the back thereof to eifect swinging of said links and thereby elevationof'said'wings, said wings being hinged to said links to swing rearwardly from their extended position, and extensible connections between the outer ends of said wings and said tractor, which connections incline upwardly and inwardly when the wing is down and downwardl 9. In a snow plow, a plow blade, means for mounting said plow blade on a tractor or the like in front of the same, wings forming extensions of the ends of said blade, a set of upper and lower links adjacent the back of the blade for supporting each wing and swingably mounting it on the blade, said links each having one of theirends pivoted to said blade adjacent the center thereof and their other ends pivoted to said wings adjacent the inner ends thereof whereby to permit the wings to be swungmpwardly from a substantially level position when adjacent the ground surface to an upwardly and outwardly inclined position when elevated, and means carried by said blade on the back thereof to effect swinging of said links and thereby elevation of said wings.

10. A snow plow comprising a pair of blades arranged in V formation, an arm extending rearwardly from each of said blades and adapted to extend along the sides of a tractor, said arms being operatively secured at their rear ends to the tractor, wings forming extensions on the outer ends of said blades, said wings being swingably carried by said blades, upper and lower links adjacent the back of each blade for mounting the wings movably on the blades, said links each having one of their ends pivoted to said blade adjacent the apex-of the V and their outer ends pivoted to said wing adjacent the inner end thereof whereby to permit thewings to be swung upwardly, and means to effect swinging of said links relative to said blades and thereby elevation of said wings.

11. In a snow plow, a V blade, wings forming extensions on the outer ends of said V blade,

said wings being pivotally carried by said blades bracket being hinged to uncover said operating mechanism for gaining access thereto.

14. In a snow plow, a plow'blade, means for mounting said blade on atractor, wings swingably mounted with respect to the ends of said blade, said wings being hinged for forward or rearward adjustment, extensible means for swinging said wings upwardly, extensible means for hinging said wings with respect to said blade, a bracket with which said last extensible means is connected, and operating mechanism for said extensible means covered bysaid bracket, said bracket being hinged to uncover said operating mechanism for gaining access thereto.

15. In a snow plow, a plow blade, means for mounting said blade on a tractor, wings'swingably mounted with, respect to the ends of said blade, said wings being hinged for forward or rearward adjustment, extensible means for swinging said wings upwardly, thrust means for determining the hinged position of said wings,

a bracket with which said thrust means is connected, and operating mechanism for said extenwith the pivots adjacent the apex of the V, and

means to swing said wings about said pivots from a substantially level position adjacent the lower side of the blade to an upwardly and outwardly inclined position adjacent the upper side of the blade.

' 12. In a snow plow, a plow blade, arms extending rearwardly therefrom and adapted to be sedured to a tractor, laterally elongated wings forming extensions 'on the ends of said blade, said wings being pivotally carried by the blade with the pivots remote from the ends of the blade to permit the wings to be swung upwardly with their lower edges outwardly inclined, and

means'carried by said blade on the back thereof to effect such swinging of said wings.

13. In a snow plow, a plow blade, means for pivotally mounting said blade on a tractor, wings swingably mounted with respect to the ends of said blade, said wings being hinged for forward or rearward adjustment, extensible means for elevating said plow blade, extensible means for swinging said wings upwardly, extensible means for hinging said wings with respect to said blade, a bracket with which said last-extensible means is connected, and operating mechanism for said extensible means covered by said bracket, said sible means covered by said bracket, said bracket being hinged to uncover said operating mechanism for gaining access thereto.

16. In a snow plow, a pair of blades arranged in V formation, means for mounting said blades on a tractor or the like, wings-forming extensions on the outer ends of said blades, said wings being swingably carried by said blades adjacent the apex of the v for elevation from a substantially level position when adjacent the ground surface to an elevated position with the lower edges of the wings inclined upwardly and outwardly due to the swingable connection of the wings to the blades adjacent said apex of the V, and thrust connections between said wings and said tractor, which connections incline upwardly and inwardly when the wings are down and downwardly and inwardly when the wings are up.

17. In a snow plow, a pair of blades hinged together in V formation, an arm extending rearwardly from each of said blades and adapted to be secured at its rear end to a tractor, said blades having cooperating flanges at their meeting ends, means for bolting said flanges together to fix one blade rigidly relative to the other one, wings forming extensions on the outer ends of said blades, said wings being pivotally carried behind said blades with the pivots adjacent the apex of the V whereby to permit the wings to be swung upwardly from a substantially level position when adjacent the ground surface to anupwardly and outwardly inclined positioned when elevated, extensible means carried by each blade on the back thereof to effect swinging and thereby elevation of said wings, and extensible connections between the outer ends of said wings and said tractor, which connections incline upwardly and inwardly when the wing is down and downwardly and inwardly when the wing is up.

18. In a snow plow, a pair of blades connected in V formation, means for mounting said blades on a tractor, wings swingably mounted with respect to the outer ends of said blades, the'pivots for such mountings being spaced substantially inward from the ends of the blades. said wings being hinged for swinging forwardly and rearwardly, extensible means on said blades for swinging said-wings upwardly, and extensible means on said tractor for hinging said wings with respect to said blades with the lower edges.

of the wings inclined upwardly and outwardly and offset upwardly from the lower edges of the blades when the wings are raised.

19. In a snow plow, a pair of blades hinged together for collapsing to a position of less width than normal, an arm extending rearwardly from each of said blades and adapted to be operatively secured at their rear ends to a tractor, said blades having engageable means at their meeting ends which may be attached together to fix one blade rigidly relative to the other one, attaching devices therefor, and a removable divider board secured between said detachable means by said attaching devices.

20. In a snow plow, a plow blade, a wing forming an extension on the outer end of said blade, upper and lower links adjacent the back of said blade, said links each having one of their ends pivoted to said blade and their other ends pivoted to said wing adjacent the inner end thereof whereby to permit the wing to be swung upwardly and simultaneously therewith swung from a substantially level position when adjacent the ground surface to an upwardly and outwardly inclined position when elevated, and means for adjusting the relative positions of the pivots to change the angle of the wing when in its upwardly and outwardly inclined position.

21. In a snow plow, a pair of blades connected in V formation, means for mounting said blades on a tractor, wings swingably mounted with respect to the outer ends of said blades, said wings being hinged for swinging forwardly and rearwardly, hydraulic jacks for swinging said wings upwardly, hydraulic jacks for hinging said wings, a bracket on said tractor for said last jacks, and valves for said jacks covered by said bracket, said bracket being hinged to uncover said valves for gaining access thereto.

22. In a snow plow, a pair of blades connected in V formation, means for mounting said blades on a tractor, wings swingably mounted with respect to the outer ends of said blades, said wings being hinged for swinging forwardly or rearwardly, hydraulic jacks on said blades for swinging said wings upwardly, hydraulic J'acks on said tractor for hinging said wings with respect to said blades, a bracket for said last jacks, and valves for said jacks covered by said bracket, said bracket being hinged to uncover said valves for gaining access thereto.

23. In a snow plow, a plow blade, arms extending rearwardly therefrom and adapted to be secured to a tractor, wings forming extensions on the ends of said blade, a pair of links pivoted to the inner end of each wing and to the blade at a point remote from the wing whereby the wings are carried by the blade to be swung upwardly and outwardly inclined, and hydraulic jack means carried by said blade on the back thereof to effect such swinging of said wings.

24. In a snow plow, a pair of blades arranged in V formation, an arm extending rearwardly from each of said blades and adapted to be secured to a tractor, wings forming extensions of each of said blades, upper and lower links pivoted to each wing and to each blade adjacent the apex of the V whereby the wings are pivotally carried by the blades to permit the wings to be swung upwardly with relation thereto, and means carried by said blade on the back thereof to effect such swinging of said wings.

25. In a snow plow, a pail of blades hinged together in V formation, an arm extendin rearwardly from each of said blades and adapted to be secured at its rear end to a tractor, means at the apex of the V to fix one blade rigidly relative to the other one, wings forming extensions on the outer ends of said blades, said wings being pivotally carried behind said blades with the pivots adjacent the apex of the Vwhereby to permit the wings to be swung upwardly, extensible means carried by each blade on the back thereof to effect swinging and thereby'elevation of said wings, said wings being hinged to said blades, and twoway hydraulic jack connections between the outer ends of said wings and said tractor, which connections positively adjust the forward and backward hinging of saidwings and rigidly fix their angular relation with respect to said blades.

26. In a snow plow, a plow blade, arms extending rearwardly therefrom and adapted to be secured to a tractor, wings forming extensions on the ends of said blade, elements pivoted remote wardly relative to the blade, and a vertical slotted guide on the back of the blade for each wins, the wing having a vertically widened plate portion guided in said guide.

27. In a snow plow, a plow blade, arms extending rearwardly therefrom and adapted to be secured to a tractor, wings forming extensions on the ends of said blade, elements pivoted remote from the ends of the blade and connected with sa'd wings to permit swinging of the wings upwardly relative to the blade, and a vertical slotted guide on the back of the blade for each wing, the wing having a vertically widened plate portion guided in said guide, said plate portion carrying rollers which travel between the opposite surfaces of the slotted guide.

28. A snow plow comprising a tractor, a plow blade mounted on said tractor and extending from the front of the tractor in a diagonal outward direction toward the rear, a rearward extension for said blade having a normally lowered operative position and means for attaching said extension to the tractor comprising a substantially vertically positioned hinge member at the forward end thereof positioned behind the rearward end of the blade, a plate attached to the hinge member and movable up and down relative to the outer end of said blade, elevating lever means connecting said plate to the plow blade mounting, a two-way hydraulic jack having a movable end secured to the elevating lever means and another movable end attached to said plow blade for fixing said extension in selected positions between said lowered operative position and an uppermost position, a second twoway hydraulic jack extending at an angle laterally relative to the first jack, having a movable end pivotally secured to the rearward side of the extension and another movable end pivotally secured to a rearward portion of the tractor opposite and above the lowered position of the extension for fixing said extension in selected positions between a laterally innermost and a laterally outermost position while said extension occupies a selected raised or lowered position.

29. A snow plow comprising a tractor, a plow blade mounted on said tractor and extending from the front of the tractor in a diagonal outward direction toward the rear, a rearward extension for said plow blade having a normally lowered'operative position and means for attaching said extension to the tractor comprising a substantially vertically positioned hinge member at the forward end thereof positioned behind the necting the extension to the plow blade mounting I for fixing said extension in selected positions between said lowered operative position and an uppermost position, a two-way hydraulic jack ex-' tending at an angle laterally relative to the elevator, having a movable end pivotally secured to l the extension'rearwardly oi the hinge and another movable end pivotally secured to a rearthe lowered position of the extension for fixing said extension in a selected position between a laterally innermost and a laterally outermost position while said extension occupies a selected raised or lowered position.

ELLSWORTH W. AUSTIN. 

